Method of making steel rule blanking die



Sept. 4, 1962 J. o. TRIMBLE METHOD OF MAKING STEEL RULE BLANKING DIE Filed April 7, 1958 FICLL FIG-3 -FICr-7 INVENTOR John QTrLmblQ.

United States Patent Office 3,052,139 METHOD OF MAKING STEEL RULE BLANKING DE John 0. Trimble, Haven-town, PiL, assignor to The Budd Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Apr. 7, 1958, Ser. No. 726,959 6 tllaims. (Cl. 76-107) The invention relates to steel rule blanking dies and methods of making such dies.

The main aim of the invention is the simplification of making such dies with a corresponding reduction in cost while retaining the desired durability and accuracy.

A main item of work and expense in making steel rule blanking dies by previously known methods was the anchoring of the steel rules in the supporting plates. This is eliminated or reduced to a minimum by the invention.

The main feature of the invention consists therein that the formed and hardened steel rule is pressed into the supporting plate thereby making the groove or retaining recess therein.

A further feature of the invention consists therein that the formed and hardened steel rule for the matching die is fitted against one side of the rule of the previously completed first die and is pressed into its supporting plate by the plate of the first die, the second supporting plate having less resistance or hardness than the first plate.

Further objects, advantages and features of the invention will become apparent from the embodiment described in the following and diagrammatically illustrated in the attached drawing.

In the drawing:

FIG. 1 is a diagrammatic section through a set of completed dies with a blank between them;

FIG. 1 is a plan view of the inverted upper die shown in FIG. 1;

FIGS. 3 to 5 are sections through the inverted upper die, showing successive steps of making it;

FIGS. 6 and 7 are, similar to FIGS. 3 and 4, sections showing the method of making the lower die;

FIG. 8 is a fragmentary, perspective section through the lower die illustrating method and means for securing a shear rule to its retaining plate;

FIG. 9 is a section similar to FIG. 8 but showing a fragmentary section of the upper die; and

FIG. 10 is a section through the lower retaining plate and showing its treatment by a grinding wheel.

The finished die set or assembly, shown in FIGS. 1 and 2 comprises upper and lower retaining plates 15, 16, upper and lower steel shear blades or rules 17, 1-8 and upper and lower supporting plates or shoes 19, 20. The blanking of sheet 21 is done between the outer upper edge of rule 18 and the inner edge of rule 17. The shape in plan view of the shear rules 17 and 18 is shown in FIG. 2, rule 18 being represented by a dash-and-dot line.

For making the upper die, a steel rule or blade 17 is first shaped to the exact desired contour, that is to the shape of the outer margin of a template 22 which in turn is an exact replica of the blank to be cutout by the finished die.

The so-formed rule 17 is placed on top of the inverted upper retaining plate consisting of steel or another suitable material sufiiciently soft for the method steps described in the following while able to withstand the impacts to which it will be subjected in the use of the die. Rule 17 is then surrounded by a dam or fillet 23 of plastic or other suitable material which will firmly adhere to plate 15 while precautions are taken that it does not adhere to rule 17.

After these preparations, rule 17 is taken off again and 3,652,139 Patented Sept. 4, 1962 hardened, the latter inevitably leading to some distortion of its shape. Rule 17 is forced back into its desired configuration by placing it on plate 15 between dam 23 and template 22.

Next, the assembly 15, 17, 22, 23 is placed into a press with a plate 24 of great hardness on top of rule 17, whereupon rule 17 is forced into the surface of retaining plate .15 forming its own retaining groove 25 (FIGS. 4 and 5). Finally, template 22 and fillet 23 are removed.

Steel rule 18, in soft condition, for the matching lower die is now formed to the inside contour of rule 17. After a darn or filling 26 of plastic or the like is provided in the inner angle between rule 18 and plate 15, rule 18 is taken out again, hardened and forced back into the space between rule 17 and dam 26. I Lower retaining or supporting plate 16 is now placed on top of rule 18, the entire assembly 15, '16, 17, 18, 26 is placed in a press, and rule 18 is forceably pressed into plate 16 forming its own groove 27. Plate 15 is harder than plate 16 at the time this action occurs to the extent that rule 18 will not, or at least not to an unobjectionable degree, indent plate 15. If upper plate 15 should be of a soft steel, the lower plate 1 6 may be of aluminum or aluminum alloy. Filling 26 is now removed.

The grooves 25, 27, formed in the respective plates 15, 16, are slightly wider toward their opening so that the respective steel rules 17, 18 are loose therein and could easily be taken out or fall out. So as to firmly retain the rules 17, 18 and so as to adjust them transversely the procedure may be followed illustrated in FIGS. 8 and 9. At certain intervals along the rule, 17 or 1 8, the edge of the groove, 25 or 27, is formed with beads 28 by means of a chisel 29, caulking tool or the like.

Slight deficiences in the matching of rules 17 and 18 can be adjusted by forcing them transversely inwardly or outwardly against the resistance of the walls of the grooves in the respective plates which hold them. Hand in hand with the matching of the rules goes the grinding in or cutting in and the formation of the cutting edges.

In pressing rules 17, 18 into their respective supporting plates 15, 16, a bulge or slope may form at both sides of the respective groove 25, 27. This unevenness may be removed or reduced by means of grinding wheel 30', while the respective rule (17 or 18) is temporarily removed prior to its final securement, as diagrammatically illustrated in FIG. 10.

The invention is not restricted to the illustrated and de scribed embodiment and its details. Particularly one of the two dies need only be made in accordance with the invention while the other die may be of other, for instance conventional, design.

What is claimed is:

l. The method of making a shear blade blanking die comprising the steps of: bending an unhardened shear blade to the same contour as a flat plate template in the shape of a blank to be cut by said die; placing said template and said bent shear blade on a retaining plate; forming a guide dam connected to said retaining plate adjacent one side of said shear blade to form a guide between said dam and said template for said shear blade; removing said unhardened shear blade from said guide and hardening said shear blade; replacing said hardened shear blade in said guide formed by said template and said dam on said retaining plate; forcing said hardened shear plate into said retaining plate while supporting said shear blade by said dam and said template thereby forming in said retaining plate a retaining groove; and of securing said shear blade in said groove of said retaining plate by establishing engagement between the sides of said blade and said groove.

2. The method of making telescopic thin-bladed rule blanking dies carried in grooves in retaining plates, which comprises, providing a template in the outline of the article to be blanked by the dies, forming a first thin die blade tothe shape of the template, placing the first die blade on a first retaining plate which is softer than said first die blade, supporting the first die blade on the sides on said first retaining plate between said template and an opposite moldable plastic material and pressing on the outer edge of the first die blade with a plate which is harder than said first retaining plate to force the first die blade for a distance into said first retaining plate, and removing the template and moldable material; forming a second thin die blade to the shape of said first die blade, placing the second die blade on the first retaining plate, retaining it in shape by said first die blade on one side and by a moldable plastic material on the other side, removing, hardening and replacing said second die blade, placing on the outer edge of the second die blade a second retaining plate which is softer than said first retaining plate and said second die blade, pressing on the second die blade with the first retaining plate to force the second die blade for a distance into said second retaining plate, removing the moldable material from the first die plate; and securing by peening said retaining plates opposite said die blades to firmly retain and adjust said die blades in position.

3. The method of making a rule-type shear blade blanking die, which comprises the following steps:

(a) providing side supporting and contour retaining means for a rule-type shear blade on a retaining die plate,

(12) placing a hardened rule-type blade which is harder than said die plate with the sides of the blade held in contoured position by said side supporting and contour retaining means,

() pressing edgewise on the blade to force an edge thereof into said die plate and form a contoured blade-retaining groove in the die plate,

(d) removing the side supporting and contour retaining means from around the blade; and

(e) when fitting operations have been completed,

finally fixing said blade in said groove.

4. The method of making a rule-type shear blade blanking die, which comprises the following steps:

(a) forming a rule-type shear blade to the desired contour while in a soft bendable condition,

(b) placing the blade on a retaining die plate,

(0) placing side supporting and holding means for the sides of the blade on the plate,

(d) removing the shaped blade and hardening it to such degree that it is harder than said plate,

(e) replacing the hardened blade on the softer plate in the position defined by said side supporting means,

(1) forcing said blade edgewise into the plate thereby forming a blade retaining groove in the plate; and

( when fitting operations have been performed, final ly fixing the blade-in position in the groove of said die plate. 5. The method of making a rule-type shear blade blanking die, which comprises the following steps:

(a) providing a contoured template,

(b) shaping a soft rule-type blade to the template, (c) placing the blade and template on a soft die plate, (4') forming a dam or fillet of plastic material which is 1 adherent to the die plate but not to the blade on the side of the blade opposite the template,

(e) removing the blade and hardening it to a condition such that it will penetrate the die plate,

(7) replacing the hardened blade in the space between the template and plastic dam,

(g) pressing on the outer edge of the blade to force its inner edge into the die plate and form a contoured groove in the die plate,

(h) removing the template and plastic dam; and

(i) when fitting operations have been performed, finally fixing the blade in the groove of the die plate.

6. The method of making telescopic thin-bladed ruletype blank shearing dies, comprising the following steps:

(a) providing a template in the outline of the article to be formed by the dies,

(b) forming a first thin rule-type die blade to the outside shape of the template,

(0) placing the first die blade and template down on a first die plate,

(d) forming a dam around the outer lower edge of the die blade of plastic material which holds to the die plate but not to the die blade,

(e) removing the die blade and hardening it to such degree that it will pierce the die plate and replacing the hardened die blade in position on said first die plate,

(f) pressing on the outer edge of said die blade to force its inner edge into said first die plate and form a groove therein,

(g) removing the template from said first die plate,

(h) forming a second die blade to the inside shape of said first die blade,

(i) seating said second die blade on said first die plate inside said first die blade with its upper edge projecting above the upper edge of the first die blade,

(j) forming a dam around the inner lower edge of the second die blade of plastic material which holds to the die plate but not to the die blade,

(k) removing the second die blade and hardening it to such degree that it will pierce a second die plate but not the said first die plate and replacing the second die blade in its former position on the first die plate,

(I) placing a second die plate which is softer than said second die blade upon the second die blade,

(in) pressing on the outer surfaces of the first die plate and the second die plate to force the edge of said second die blade into said second die plate and form a groove therein,

(n) removing the plastic material from said first die plate; and

(0) when fitting operations have been performed, finally fixing the blades in the grooves of the die plates.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS 317,950 Great Britain Aug. 29, 1929 

